Abstract
BACKGROUND: In the United States, the prevalence of anemia, iron deficiency (ID), and iron-deficiency anemia (IDA) during pregnancy remains largely unknown as data at the national or state level are limited or nonexistent, respectively. OBJECTIVES: In an effort to identify opportunities to improve maternal health surveillance, we assessed the feasibility of anemia, ID, and IDA surveillance among first-trimester pregnancies using electronic health records (EHRs). METHODS: We identified pregnancies among Kaiser Permanente Northwest members aged ≥18 y during 2005-2016 with first-trimester prenatal care (n = 41,991). Earliest laboratory test results for hemoglobin or hematocrit and ferritin were selected. We describe the proportion of pregnancies screened for and the prevalence of anemia, ID, and IDA; the concordance of anemia status by hemoglobin compared with hematocrit; and the proportion of pregnancies with laboratory-confirmed anemia that also had an International Classification of Diseases diagnostic code related to anemia. RESULTS: Identified pregnancies included women who were 73.1% non-Hispanic (NH) white, 11.5% Hispanic, 8.5% NH Asian/Pacific Islander, and 2.9% NH black. Hemoglobin and hematocrit results were available for 92.7% (n = 38,923) pregnancies. Anemia prevalence was 2.7% (n = 1045) based on hemoglobin <11.0 g/dL or hematocrit <33%; 45.2% of anemia cases had both low hemoglobin and low hematocrit. Among pregnancies with anemia, 18.9% (n = 197) had a ferritin result; of those, 48.2% had ID (ferritin <15 μg/L). In pregnancies without anemia, 3.4% (n = 1275) had a ferritin result; of those, 23.5% had ID. Based on 1472 pregnancies with both anemia and ID assessed, prevalence of ID and IDA was 26.8% and 6.5%, respectively; estimates likely represent selective screening. CONCLUSIONS: EHR data have potential to monitor anemia prevalence and trends in health systems where prenatal anemia screening is nearly universal. However, if iron assessment is not routine, then representative estimates of ID or IDA are unattainable.